A conventional pillow generally includes a flexible outer enclosing layer or tick often made of fabric and encasing a resilient filler which may be of a unit of continuous nature such as a sponge rubber or foamed synthetic elastomeric block or may be of a non-continuous nature as in down, resilient or natural fibers or particles (e.g., ground foam particles). A variety of factors go into the comfort level a user associates with a particular pillow as in the materials utilized, the density of the cushioning materials used (individually and in combination), the firmness (e.g., Indentation Force Deflection or “IFD”—again either individually or in overall combination), the shape (e.g., thickness, depth, or general configuration), etc. These factors also combine together to provide a user with a particular feel which forms part of the overall comfort level a user associates with a particular pillow. The same holds true for other types of cushioning devices as in seat cushions, but is particularly pronounced relative to the extended direct face or head contact associated with head pillows.
The comfort level that a particular user desires in a pillow to meet that individual's sleeping needs, varies from person to person as well as on a time basis with respect to one user as a person's pillow support needs can change on a seasonal basis and even on a night to night basis. People can also be very adamant about having the right pillow and can find great discomfort and sleep poorly if the pillow does not meet the user's desired comfort level. Some user's also have medical conditions that favor one comfort characteristic over another in a pillow, as in a person with a spine problem may prefer a different firmness level over one not having such a medical condition. The desired comfort level can also be a matter of habit or what a user has grown accustomed to over the years. Thus, a pillow that has one type of comfort elements combination may be deemed the most preferred by one person only to be felt by another to be a poor choice.
The comfort level that a person feels relative to a particular cushion device can also vary over time in the pillow itself as in individual filler material clumping and even larger internal cushion elements moving in position within the pillow as well as a general degradation in quality of a cushioning element such as a break down in a fiber or particle filler element.
There also exists adjustable air bladder insert pillow embodiments which can provide a degree of variation when provided with means to adjust the pressure level (ball pump with one way valve), which may be favored by some; but for other individuals the “feel” attributed to such a pillow renders it non-desirable, which might be attributed, in part, to the combination of cushioning material characteristics relative to the layering often involved (e.g., plastic bladder skin/foam cover), and the heat retention or release characteristics associated with the comfort elements combination involved.
Additional factors associated with a person's comfort level with a pillow include cleanliness, which often is closely associated with the ease of cleaning the pillow (e.g., some pillows render it difficult to clean due to the material that is used and/or how materials are used in combination within the pillow (e.g., a non-accessible single tick outer covering with loose filler down is an example of a difficult to clean pillow while some foams with high heat retention may cause cleaning needs in short time frames due to perspiration build up, etc.)). While a cleanliness level is certainly desirable for individuals at home, other facilities such as hotels are subject to even higher requirements for making sure there pillows are clean and, from a cost standpoint, it will be important to those facilities that cleaning the cushions can be readily accomplished (a pillow that is not easily broken down and/or reassembled when certain pillow parts are subject to cleaning or more frequent cleaning is undesirable).